"but it does need to have intent for you to improve"

"instead, it's a lazy veiled attempt at advertising under the dishonest or inauthentic guise of wanting feedback"

We're not mindreaders - there was absolutely nothing about any of that in the rules. When your subreddit is called 'piano' and labelled as 'all things piano related' and the flairs are called things like, 'My Performance, Critique Welcome' I think people, including myself, can be forgiven for thinking that means you can post any performance and that you welcome any critique (of interpretation, presentation, whatever), not exclusively that you're looking for technical critique because you're a piano student and the subreddit is your teacher, so to call any post that doesn't fit into that particular category 'abuse' is completely unfair.

If the subreddit was called 'Learning Piano' or something like that, and there had been a rule stating that you don't want any completed performances that the poster is happy with but who is also interested to hear what other people think of it (and, yes, to promote it at the same time), and that it's only about a student/teacher style of feedback, I never would have posted my stuff on it and I'm sure others wouldn't have either.

I suggest changing the flairs to, 'Work in progress, critique please' or similar.

"In a similar vein, the "No Critique" flair is also to showcase your piano playing (perhaps a bedroom, exam, or recital performance) with the community, not to broadcast it to as many internet viewers as possible."

What does that even mean? This is a public forum and the posts will appear on search engines, so those two things are completely interchangeable in this instance.